Titan's dense, smoggy atmosphere

. The surface of Titan is hidden from view by a hazy layer of smog, giving it a fuzzy, tennis-ball appearance in a Voyager 1 image (left) taken on 4 November 1980. When illuminated from behind, the dense atmosphere forms a crescent several hundred thousand meters above the satellite's surface (right) seen by Voyager 2 on 25 August 1981. The extension of blue light around the moon's night side is due to scattering from smog particles in the sunlit portion. The Cassini spacecraft is expected to drop its Huygens Probe into Titan's atmosphere in 2004. (Courtesy of JPL and NASA.)